Question

A man can row a boat at 8 km/h in still water. If the speed of the water current is 2 km/h and it takes him 2 hours to row to a place and come back, how far off (in km) is the place?

• A. 7.5 km
• B. 6 km
• C. 9.5 km
• D. 10 km

Answer 1

Answer: (A)

7.5 km

Answer 2

Speed downstream = 10 km/h, speed upstream = 6 km/h. Total time = $\frac{d}{10} + \frac{d}{6} = 2$ hours. Solving for $d$ gives $d = 7.5$ km.